Can't ship right now

I'm sick of falling for these! Who made this up and why is it a regular thing now to offer great prices, say you can't ship now, then change the price to 25x that amount on the day you can ship? Does it really work, to see what kind of interest there is and price accordingly? Because my only interest was the fact that they were great deals. I didn't go "eh $5, $50, potato patatoh" and buy the stuff anyway! Not one item was offered at even close to a bargain after their adjustment.